diff --git a/src/ncrypto.cpp b/src/ncrypto.cpp
index f98ad56..e935eb8 100644
--- a/src/ncrypto.cpp
+++ b/src/ncrypto.cpp
@@ -17,15 +17,13 @@
 
 #if OPENSSL_VERSION_NUMBER >= 0x30200000L
 #include <openssl/thread.h>
-#ifndef OPENSSL_NO_ARGON2
-#include <vector>
-#endif
 #endif
 
 #include <algorithm>
 #include <array>
 #include <cstring>
 #include <string_view>
+#include <vector>
 #if OPENSSL_VERSION_MAJOR >= 3
 #include <openssl/core_names.h>
 #include <openssl/params.h>
diff --git a/tests/basic.cpp b/tests/basic.cpp
index 61c5e13..138797d 100644
--- a/tests/basic.cpp
+++ b/tests/basic.cpp
@@ -215,6 +215,42 @@ TEST(Ec, getCurve) {
   ASSERT_EQ(curve, NID_X9_62_prime256v1);
 }
 
+TEST(Ec, GetCurves) {
+  std::vector<std::string> curves;
+
+  bool result = Ec::GetCurves([&](const char* name) {
+    curves.push_back(name);
+    return true;
+  });
+
+  ASSERT_TRUE(result);
+  // Should have at least some built-in curves
+  ASSERT_GT(curves.size(), 0u);
+
+  // Check that common curves are present
+  bool hasP256 = false;
+  bool hasP384 = false;
+  for (const auto& curve : curves) {
+    if (curve == "prime256v1" || curve == "P-256") hasP256 = true;
+    if (curve == "secp384r1" || curve == "P-384") hasP384 = true;
+  }
+  ASSERT_TRUE(hasP256);
+  ASSERT_TRUE(hasP384);
+}
+
+TEST(Ec, GetCurves_early_exit) {
+  int count = 0;
+
+  // Test that returning false stops iteration
+  bool result = Ec::GetCurves([&](const char* name) {
+    count++;
+    return count < 3;  // Stop after 2 curves
+  });
+
+  ASSERT_FALSE(result);
+  ASSERT_EQ(count, 3);
+}
+
 // ============================================================================
 // EVPKeyPointer tests